hi guys, i have an 89 gta that i cant get to start. i got the car about a year and a half ago and the car had sit for around 9 years or so. ive slowly been going through it and have cleaned what use to be gas out of the tank, new pump and filter, new bosch injectors. the original keys were lost in a house fire, so i bought a new cylinder and put resistors in line until it turned over. the car starts if somebody sprays gas down the intake so i have spark. i also have pressure at the rails. any help would be appreciated.

 

Since the engine will fire with fuel being administered the ignition system is obviously functioning.

Verify the INJ1 and INJ2 fuses in the main interior fuse panel are intact. Also verify the VATS 10A fuse in the swing-down convenience center is intact.

If both banks of injectors have a 12V supply, the ECM is probably not providing injector pulses.

The ignition system provides reference pulses to the ECM to operate the injectors, and that is probably happening since the ignition system is working.

The VATS system can interrupt injector pulses from the ECM if it is not satisfied with the key resistance AND if the VATS module is not signalling the ECM with the proper signal. If you scan for error codes when the vehicle does not start and retrieve a "53" it is likely due to an incorrect VATS resistance. This code does not store in memory and must be retrieved while the condition exists.

If you determine the problem is VATS further diagnosis will be necessary.

 

VATS can be bypass but needs tuning hardware and software. Maybe local tuner could do it and burn you a PROM. Not complicated if you have proper equipment and knowledge.
Best of luck